Nonflammable cleaning solvent



Patented Feb. 18, 1936 PATENT OFFICE 2.031.144 w v NONFLAMMABLE CLEANINGSOLVENT Merrill A. Youtz, Hammond, Ind., assixllor to Standard OilCompany (Indiana), Chicago, 111., a corporation of Indiana No Drawing.Application my 14, 1930,

Serial No. 457,991

'1 Claim.

This invention relatesto cleaning solvents and it pertains moreparticularly to non-flammable mixtures of light hydrocarbons andhalogenated solvents.

The object of my invention is to provide a cleaning solvent containing alarge amount of flammable light hydrocarbons protected by chlorinatedsolvents, so that when the cleaning solvent is evaporated both thevapors and the residual liquids are non-flammable.

Light hydrocarbons. such as benzine, petroleum naphtha, etc, areexcellent solvents and are relatively inexpensive, but they aredangerous because of their flammable and explosive nature. Nonflammablesolvents, such as carbon tetrachloride, are non-explosive, but are expensive and are objectionable because they dissolve too much oil from furs,woolen goods; etc. Carbon tetrachloride has been added to relativelyheavy naphthas for rendering the evaporated vapors non-explosive, andattempts have been made to render the naphtha non-volatile by theaddition of waxy bodies. In suchcases, when the initial mixture is onthe verge of flammability, the residual solvent very soon becomesflammable and such mixtures are therefore objectionable and dangerous.

I have discovered that by proceeding directly contrary-to the abovepractice, both the evaporated vapors and residual liquids may containhigh percentages of light' hydrocarbon solvents explosive. naphthainstead of a non-volatile naphtha and I select flammable andnon-flammable solvents (such as petroleum naphtha) and still be non- Iuse a relatively volatile petroleum V of substantially the samevolatility for my mixture. Such a mixture may be evaporated to anydegree and still maintain the same ratio of flammable solvent tonon-flammable solvent, both in the evolved vapors and in the residualliquid.

In other words, I provide a mixture which cannot 'readilybe fractionatedby distillation.

As a specific example of my cleaning solvent this'solvent is usedas adry cleaner and a large amount of it is evaporated, the gaseous or vaporphase will always be non-flammable because it will always contain about60 to 65% carbon tetrachloride. Likewise the liquid phase will benonflammable because it will always contain the same proportion ofnon-flammable solvent. There no tendency for the naphtha to concentratein the residual solvent. Consequently I am enabled to employ largerproportions of naphtha in the" mixture than has heretofore been possiblewith-. out danger of flammability. a

As another example of my invention I may use a heavier mixture. I mayuse acetylene tetrachloride with petroleum naphtha, whose boiling l5range is about 290 to 325 F. In fact, I may use any mixture of flammablehydrocarbon solvents with non-flammable solvents as long as thevolatility'of one is substantially the same as the volatility of theother so that there will be no tendency of the mixture to fractionate orseparate into different components by distillation or evaporation.

By departingfrom prior usage and employing a flammable solvent ofsubstantially the same volatility as the non-flammable solvent, I haveproduced several noteworthyresults. The 501- vent mixture is as safe touse under any conditions as carbon tetrachloride, but at the same I timeit is less expensive than carbon tetrachloride, it-does not have asgreat a tendency to remove natural oils from furs, woolens, etc.,' andit combines the properties of hydrocarbon solvents with chlorinatedsolvents.

While I have described preferred embodiments i of my invention indetail, I do not limit myself tosaid details except as defined by thefollowing claim.

A dry cleaning solvent comprising a mixture of, petroleum naphtha havinga boiling range of about Hill-220 F. with carbon tetrachloride inproportions of about 35 to 40 parts by volume of petroleum naphtha toabout 65 to '60 parts by volume of carbon tetrachloride whereby thedrycleaning fluid is substantially non-flammable, its vapors aresubstantiallynon-flammable. and it leaves a substantially non-flammableresidue'upon evaporation.

